On his first trip to Beijing as U.S. Secretary of State, John Kerry arrived with an entreaty. As warmongering from North Korea reaches earsplitting levels, Kerry had petitioned Chinese leaders to rein in an isolated country that Chairman Mao Zedong once said was as close to China as lips are to teeth. On April 13, after a day of talks with China’s top brass, Kerry met with reporters at Beijing’s state-run Diaoyutai Hotel, a gilt-and-chandelier confection, and spoke positively of China’s commitment to pressing for peace on the Korean Peninsula. “There’s no question in my mind that China is serious, very serious about denuclearizing” North Korea, he said, describing his overall talks with Chinese leaders as “beyond what I anticipated.”

Kerry met with a cavalcade of newly installed Chinese rulers, including Communist Party General Secretary Xi Jinping, Premier Li Keqiang and foreign policy chief Yang Jiechi. The U.S. Secretary of State said he and Yang had issued a rare “joint statement” on their shared commitment to denuclearizing the Korean Peninsula.

But Kerry’s rosy pronouncements notwithstanding, China’s support of dismantling North Korea’s nuclear-weapons program does not appear to be a break from its previous stance. Indeed, Beijing has consistently said it supports peace in the region, as well as a cessation of North Korea’s nuclear ambitions.

Referring to hopes to restart nuclear talks with North Korea, Kerry said Beijing and Washington would conduct “further discussions to bear down very quickly with great specificity on exactly how we will accomplish this goal.” It was unclear, however, whether holding such discussions amounts to a true breakthrough. On Friday, Xinhua, China’s official news agency, published an op-ed saying Kerry should be “aware that his country holds the key to alleviating the suffocating tensions on the Korean Peninsula.” The U.S., meanwhile, has repeatedly characterized Beijing as key in dealing with North Korea. On Thursday, U.S. Director of National Intelligence James Clapper told Congress: “If anyone has real leverage over the North Koreans, it is China.”

Yet as Kerry met on Saturday with Chinese leaders, it was not certain what Beijing could do to pressure Kim Jong Un, the 30-year-old grandson of Kim Il Sung, who first led the socialist family dynasty that has ruled North Korea since its inception. China helps prop up the North Korean regime financially. But the young Kim has shown little inclination to hew to Beijing’s wishes for a peaceful, nonnuclear Korean Peninsula. On April 12, Pyongyang described nuclear weapons as a “treasured” commodity.

In recent years, North Korea has shelled a South Korean island and torpedoed a South Korean ship. Since taking power, Kim has overseen a rocket launch and an underground nuclear test earlier this year. New U.N. sanctions were imposed in February after that nuclear test. Ever since, the invective flowing from Pyongyang has intensified further, and an emergency hotline to South Korea has been severed.

Speculation is mounting that North Korea will soon launch a missile test, perhaps as early as April 15, the anniversary of the birth of Kim Il Sung, North Korea’s founder. (An attempt last year to launch a satellite on Kim’s birthday failed.) Any such test, which could involve a medium-range missile with the capacity to reach the U.S. territory of Guam, would contravene U.N. Security Council resolutions. On Saturday, Kerry described North Korea’s recent actions as “unwise and unnecessary and unwanted and provocative.”

Last week, a leaked report from the U.S. Defense Intelligence Agency stated with “moderate confidence” that North Korea has the ability to launch a ballistic missile with a nuclear warhead. It was an assessment that some believe was merely stating the conventional wisdom about North Korea’s expanding nuclear capacity. But the White House downplayed the report.

While in Seoul on Friday, Kerry spoke bluntly about the effect a possible missile test might have on regional affairs: “If Kim Jong Un decides to launch a missile, whether it’s across the Sea of Japan or some other direction, he will be choosing to ignore the entire international community, and it will be a provocation and unwanted act that will raise people’s temperatures.” (After Beijing, Kerry will head next to Japan, as part of his four-day Asia tour.)

In recent weeks, Beijing has expressed frustration with North Korea’s aggressive stance. Earlier this month at an international forum in southern China, Xi issued what was viewed as a veiled reference to North Korea: “No one should be allowed to throw a region and even the whole world into chaos for selfish gains.” China’s Foreign Minister Wang Yi has said his government will “not allow troublemaking on China’s doorstep.” Earlier this year, an editor at Study Times, an ideological weekly affiliated with the Chinese Communist Party, wrote an op-ed in the Financial Times headlined “China Should Abandon North Korea.” (He was later pulled from his position at the Study Times.)

One Chinese academic with official connections says there have been no recent top-level exchanges between China and North Korea — a troubling assertion. On Saturday, Kerry presented a different picture. “Obviously they communicate,” he said, referring to Beijing and Pyongyang.

But even if they talk, what options does Beijing have? It could start reducing aid to North Korea, particularly deliveries of fuel. But any collapse of North Korea would trigger a mass refugee influx into China. And North Korea remains a useful buffer for China in a region where Beijing fears the U.S. is building up its military presence. True to form, Xinhua condemned the U.S. for “fanning the flames” on the Korean Peninsula. The blame game shows no sign of ceasing, no matter what joint commitments are made between Beijing and Washington to pursuing a nonnuclear North Korea.